There are two main ways to get both to activate, first to switch Charizard into something that will switch out while stealth rock is in play. Belly Drum on the switch to get the Drum, Salac, Blaze boost. Due to the anticipated prevalence of sandstorm this is not recommended.
The second way is to use substitute to set up a sub, then drum down to the salac boost and sweep. This is safer on the whole but still not that easy to pull off
In the future questions like this can be asked in the simple question thread.