Hi titu_quz, welcaome to BT. Apni sob gulu gan ke ekta folder e rekhe tarpor oi folder ta ke .torrent file banaben. You can check this thread http://www.banglatorrents.com/help-and-support/22-how-to-make-a-torrent-and-upload-on-bt.html
If you need more help with that please let us know.