"Zap" is a convenient feature that allows to create LP token, UNITE-ONE or USHARE-ONE in this case; and stake it in autocompounder using single asset, in a single transaction. You can easily choose, which asset you want to use by selecting it from drop-down menu (see screenshot below). You have a choice to use your UNITE/USHARE or ONE or WONE or, an already created LP token if you did that manually on ViperSwap.