Anyone know where I can get an instruction manual as i have no idea how to erect the two side tents

That is huge, it is like a house!

https://www.google.com/search?q=Northwest+Territory+Olympic+Cottage+Tent

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Wow! That is not a new model. :-) All I can suggest is that you look for YouTube videos of setting up tents, or lay it out with a couple of friends who have a lot of experience with different tents and give it a try.

I don't know what kind of tent you have but there are many videos on youtube.
erecting tent YouTube

building tent YouTube

making tent YouTube

What tent is it? They're usually pretty intuitive, but with a name or picture, I should be able to help.

Free online instructions:

https://www.manualslib.com/manual/1185642/Oztrail-Villa-Dome.html?page=4

Visit this site for the information you are requesting: www.ukcampsite.co.uk/tents/p/Outwell-Colorado-5/369

It does not come with instructions oddly.
However, start with the external frames and then hang the main inner tent onto it. Finaly drag the flysheet over at the end.
The middle legs sort of cross over towards each other and meet in the middle at the bottom - this is crucial!

Hope this helps.
Paul

Peg out the "brown" ground sheet of the inner tent and hold it up like a standard ridge tent.
Put the two shorter upright poles on the inside of the compartment (with something under the feet to prevent damage to the ground sheet). Put the 40mm tubes on the spike that pokes through, and then put the ridge pole on the outside.
Everything should then hold in place while you put the fly sheet over the top with the 2 longer poles at the front.......

tip - line up the seam on the fly sheet with the front of the inner tent as you peg it out....
Good luck

If you go to www.coleman.com Use the product services link for product manuals. You can then choose tents. Or you can use this link:
http://www.coleman.com/coleman/images/pdf/2000000136.PDF