anyone please I'm stuck

The best way to level up in the Dark Zone when playing solo would be to go around and killing the named bosses located at each of the Landmarks (Area will be marked purple with a purple fist (Will be grey if the boss has recently been killed and not respawned)). You should also kill regular enemy NPCs along the way just for the sake of continuing to earn Dark Zone xp. By doing this you will earn Dark Zone xp, Dark Zone credits and loot which you can then take to an Extraction point so you can then access the items outside of the Dark Zone (Will be located in your Stash box found in any Safe House or the Base of Operations).
Dying in the Dark Zone will cause you to lose some xp and some Dark Zone credits, any contaminated items that you have picked up whilst in the Dark Zone will also be dropped. After respawning you can go back to where you died and pick up the credits and items, as long as another player hasn't come along and taken them.

I would recommend getting to level 30 max xp so that you will be able to loot the best level gear you can from the Dark Zone as well as obtaining Phoenix credits which is the end-game currency for The Division which is used to buy very good weapons, gear and blueprints.

okay thanyou do you recommend completing or getting to level 30 first?

You definitely need to reach level 30 first before doing anything worthwhile in the dark zone. Some early on dark zone loot may help but all of the decent gear is found using phoenix credits, mostly.