How do I know if a masjid is upon the correct manhaj? Is it enough if I just ask them are they salafis or do I need to test them in some way by asking. For example by asking "who are your scholars" or "can u rebel against the ruler" If im interested in studying tajweed or Arabic in the masjid

Ustadh AbdulAziz al-Haqqan

When u study under a teacher u should know him may Allah reward u not just go to anyone