Don't panic.
Check you have all the bits. Parts diagrams on a couple of spares websites.
Check all the bits look ok, no excessive wear, damage etc.
Work out if & what you need, cost it.
Then have a look on the previous articles on mod 35/50 triggers & see if it's something you feel you can do. if it is then order the parts if your sure it seems like a good idea in terms of cost, final value, practicality.
Then just take your time & set about it in an organised fashion. If things don't go right first time have a beak, read up on it again & settle down to it when you are ready.
Looks daunting, is fiddly but others have done it.....