Could you recommend some good mods and how to install them on the steam version please
Ask and you shall receive:
Current Version Mods:
Sword of Damocles
Only just got started with this one but it's one of the most established and complete mods for M&B. You're a king and you have to manage a kingdom. It features new dimplomacy, kingdom management, troop management... Plus, a huge amount of new items and units. It's very impressive but definately for M&B veterans.
http://forums.taleworlds.com/index.php/board,117.0.html
Lords and Realms
Adds a lot of depth to the game and adds kingdom management but sticks closer to vanilla than SOD. A good interim step before stepping up to the challenge of SOD.
http://forums.taleworlds.com/index.php/board,120.0.html
Caldaria at War
A rebalance of vanilla giving more depth to the factions. Re-worked troop trees, new weapons, combat etc. This mod is recommended if you want an enhanced vanilla experience without too much change to the overall feel.
http://forums.taleworlds.com/index.php?topic=49376.0
For older versions:
Onin No Ran
Feudal Japan total conversion. Far from complete and a bit limited in scope. However it's a fun hack and features quests, factions and several 'classes'. Work unfortunately seems to have stopped on this one
http://mbx.streetofeyes.com/index.php?board=42.0
The Last Days
LOTR total conversion. Do I need to write anything further to sell it?
Work
is being done to convert this to Warband and I will be downloading it on day one of release, locking myself in my room and will start to use words like 'forsooth' and 'verrily' on a regular basis to help immersion. I may even dress up as a Dwarf.
http://mbx.streetofeyes.com/index.php/board,20.0.html
A Song of Ice and Fire
TC based on the books by George R. R. Martin. Haven't played it myself but a friend is a big fan of the books and a follower of this mod. Work in also being done to port this to Warband.
http://mbx.streetofeyes.com/index.php/board,55.0.html
I've played others which have come-and-gone, some of which were very basic compared to today's offerings. It's crazy to think that some of these mods started in M&B beta as far back as 2005.
Edit:
Steam install is identical to normal version install. Shove them in your modules folder and select them from the drop-down at the startup menu.