vaal double strike

hello i am trying to follow a build
https://www.poebuilds.net/builds/duelist/block-double-strike

but i changed my double strike to vaal double strike as suggested in the build but how to use it
it take long time to replenish souls, it no more possible to use the skill frequently

how the gameplay is suposed to be with that vaal double stike please

Vaal gems come with both the normal and Vaal versions of the skill built in. Use the normal version for clearing and whatnot to build up souls, then use the Vaal version as needed when it's charged (or save it for bosses/hard mobs).

You get 1 soul per mob killed, and can also gain charges for damaging rare or unique mobs.

i see , thx but that skill is on my right mouse button how to i easily switch from one to the other

when i presss control only the lower bar have secondary skill

Left-click on the skillbar slot that you want to change.

thx a lot i bound it to a key , i will use it like a burst on boss i guess