Check this to work with mnemonics/keys and this to deploy a wallet and send a transaction.

Please make a note that wallet is deployed by first outgoing tx (not incoming one), so you need some TON to be on your acc before you'll start deploying it.

For brand new wallet your sequence is like this:

• create key, compute an init data and convert this to your (future) wallet address as in line 49. If you open your address in explorer at this moment - you'll see zero balance and inactive state.
• transfer some TON (from Exchange or whatever) to your new (still inactive) address. Explorers will show "in" tx and non-zero balance, but state of your acc will be "inactive" still.
• make outgoing transaction (to your own or other address) as in lines 58+ - this will make your acc Active.