Size of fittings.

It takes 2 people. Open the bleeder on the slave cylinder, hold your finger over it while the pedal is pumped, releasing the pressure when the pedal is down.. Once it starts pushing fluid thru, close the bleeder, pump 3 times, open bleeder with pedal down. Repeat till clutch feels good. If you are replacing the master cylinder, bench bleed it 1st. Be patient, this all takes awhile.

If you mean you step on the clutch, put transmission in gear and release clutch with no engagement (pedal returns to top position) there is a good chance your clutch disc or pressure plate, or both are worn out and need replacing.
If your clutch pedal is going to the floor and not returning there could be a leak in the system, a bad clutch master cylinder or a bad slave cylinder on the transmission. Check the fluid level in the clutch master cylinder. If it is low or empty you have a leak or component failure. Visually inspect clutch master, line, slave cylinder for fluid leaks. replace as needed. If hydraulics are o.k., suspect clutch disc/pressure plate.

there are different ways to bench bleed the master depending on the tools available to you... did you receive a fitting, with or without a port for a small hose, in the new master box? if not then you should make one or get one at the parts store. you need to put the master in a vice (from the mount, not the body) and fill it with fluid. this is where the fitting comes in handy, you are going slowly depress the piston about half way at first having the fluid that comes out the port directed back into the reservoir with a hose. keep the hose submerged. if a vice and fittings are not available, you can mount the master in the vehicle, connect the line and fill with fluid. disconnect the line from the slave cylinder and submerge it in a container. press the pedal by hand slowly. make sure the line stays submerged and the master is never run dry. if everything is kept clean, you can reuse the fluid from the catch container.

If it is a hydraulic clutch, and not cable operated, there will be two cylinders. A clutch master cylinder will be mounted on the firewall next to the brake master cylinder. One steel line will go from the master cylinder down to the slave cylinder bolted onto the transmission housing where the clutch lever extends out of the housing. Other than bleeding the slave cylinder, no adjustments are necessary on hydraulic clutches. Cable operated clutches have an adjusting mechanism to take up slack when the clutch disc wears. The adjuster will be inside the engine bay.

if it,s hydrolic look to put in fluid.

Yes all 92-95 civics have a hydraulic clutch system. it starts at the pedal. Pedal pulls a plunger in the clutch master cylinder which is found bolted through the firewall under the hood on the drivers side. The master cylinders resivoir is bolted to the drivers side strut tower and connected to the master cylinder with a rubber hose. A line from the master cylinder runs along the firewall tirades the passenger side wheel then turns to the front of the car and is connected with a fitting to a rubber hose. The rubber hose runs to your clutch slave cylinder. The slave pushes the clutch arm. Your clutch pedal is staying on the floor because there is no back pressure to push it back up. You have air in your clutch system. First find out why (find leak or just top up clutch master cylinder with brake fluid if no leaks) then bleed your clutch. If your clutch line is rusted there is a coupler mid way in the line on the firewall. Will save you from removing the whole line maby. And there is no need to bench bleed the clutch master cylinder. My guess is your slave cylinder is leaking. It right on the front of the transmission. Pull back the rubber boot over the end of the slave cyl. and check for fluid leaks. The bleed screw is on top of the slave cyl. Find/fix leak, fill resivoir, pump clutch 10 times then HOLD. Open bleeder screw, watch for fluid and air sputtering out or just air. CLOSE valve, release clutch. REPEAT until clutch works keeping resivoir topped up. You may also open bleeder screw and pump clutch to get fluid into the system before you do the bleed process. Keep in mind brake fluid eats paint and is not very nice on your skin or in your eyes so be carefull with it. There may also be an off chance your pedal sticks because the clutch itself is badly broken but it's not really very likely.

just look at the plugs and if it is the same and the same engine size it should work fine

These cars use a Hydraulic system for their clutches. chances are if your pedal is low it is time for a new clutch providing your slave cylinder is ok. With this system you will have a master cylinder for the clutch and a slave cylinder which moves the clutch itself when push the pedal. you need to make sure their is no leaks in these two parts.

I hope this helps, Allen

clutch master cylinder is located drivers side firewall,right next to brake master cylinder. it has small shot glass size fluid resevoir mounted above it,fluid is fed through hose down into clutch master. clutch master cylinder has a rod mounter on ft of it that goes through firewall and attaches to clutch pedal under dash . clutch slave cylinder is mounted on ft passenger side of transmission assy. most common leak is from master cylinder,you would be able to look under dash ,follow clutch pedal up to where it attatched to clutch master pushrod.follow that rod to wear it meets up to a small 1 1/2" or so rubber boot.fluid will be leaking from that boot if master is leaking.