For the beginners you can try this using washable tints before you go. Dark brown is among the admired hair color by most individuals due to its cool nature.
Nicen Easy No Ammonia Hair Dye Dark Brown 79 https://www.superdrug.com/Save-%C2%A31-on-selected-Nice-N-Easy/Nice'n-Easy-No-Ammonia-Hair-Dye-Dark-Brown-79/p/188698
Semi Perm 3dbr Dark Brown https://tintsofnature.com/ton1blk-1
Permanent Hair Color Dark Chestnut Brown 3n https://thrivemarket.com/p/naturtint-permanent-hair-color-dark-chestnut-brown-3n