This is a pretty straightforward Build.
Drow get
Superior Darkvision -which is double the normal 12m/40 feet range of regular darkvision- usually there is a limitation on the Rogues ranged sneak attack from height where the darkvision doesn't cover the range of the weapon. In addition rogues are only able to use simple/rogue ranged weapons which usually means Shortbows and light crossbows, which limit damage. This build fixes those issues.
Starting Stats:
Str: 14
Dex: 17
Con: 14
Int: 9
Wis: 10
Chr: 10
You can play with these a bit but 17 Dex is important for later.
Higher strength helps with carry weight, jump distance and shoving/resistance to being shoved
I strongly recommend sticking with 14 con.
The main four skills to have are - Athletics, Acrobatics, Stealth, Sleight of Hand you get Perception for free as a Drow.
At Level 3 you will take Thief as your Subclass.
At Level 4 you Will take the Feat
Weapon Master and choose the extra point in Dex and the following weapons: Longbow, Scimitar, Heavy Crossbow and whatever for the 4th.
At this point with a Heavy Crossbow + 1 at Height you are looking at 1D10 + 5 + 2d6 sneak attack + Poison damage/fire damage with a +7 proficiency Bonus and Advantage on attacks to a range of 24 Meters/ 80 Feet.
That's a
damage range of 9- 31 damage per hit with a very high chance to hit due to
Advantage on all attack rolls.
You will also have high mobility, resistance to being shoved, great jump range and a very good chance of shoving others so you will be the undisputed "King of the Mountain". In addition as a rogue you get
Dash and Disengage as a bonus action but a solid shove is a good play if someone tries to close the distance with you.
If you want to throw Wyvern Poison in the Mix and Potion of speed you go to 1d10 + 5 + 2D6 + 7D6 damage.
15- 80 damage.
13- 68 damage (second attack).
Obviously there are other buffs which will increase damage and accuracy. Bless, Cats Grace, Ritual Dagger buff, Gloves of Power with absolutes Mark.
Happy Murdering!
