Note the use of бы 'would' without a љсли-clause:
   Ї бы ћчень хотљла пойтќ с тобћй. I'd really like to go with you.
   Ї хотљл бы познакћмиться с нќм. I'd like to meet him.
   Мнљ бІло бы удћбнее встрљтиться в сљмь. It would be more convenient for me to meet at seven.
   На твоём мљсте ї бы купќла ещё стџл. If I were you I'd buy another chair.
   Ї бы лџчше пошлђ в теђтр. I'd rather go to the theater.
Conversely, you can have a љсли clause alone; use this construction to express wishes:
   Љсли бы тћлько Сђша пришёл! If only Sasha would come! If only Sasha had come!
Note the use of бы without -л- in the construction meaning If it weren't (hadn't been) for X...
   Љсли бы не Сђша, у нђс нљ было бы билљтов. If it weren't for Sasha, we wouldn't have any tickets.
   Хорошћ бы ћн пришёл. (informal) I hope he comes. (Lit., 'It would be good if he came.')
To express 'then' in an if... then... situation, you can use either тћ or тогдђ.
   Љсли ћн придёт, тћ/тогдђ ї емџ скажџ. If he comes, then I'll tell him.