well it depends on the equips you can afford.. if i were you considering you are new... buy %luk equips (it doesnt matter how high) and then scroll the gear with dex but do this only when you find out how much dex you need to wear end game cane... and dont forget to choose your base dex wisely too... alot of people end up giving a base dex of 25-50 so when they hit 120 they can wear the end game dagger/claw but then they get more funded and realize they put too much dex...
dont go more than 40 base dex if you do you just ruined it. also like ^^ said it depends on what equips you have/can afford. for example like evo rings and HTP and CZak helm can rlly help! plus the cannoneer skill
Honestly... Nobody can really help you without us knowing how much funding you have / what you have already.
A dexless Phantom isn't very hard as their beginner skill gives +40 already.
You haven't told us the slightest bit that would help. Do you have a cannoneer? How much funding do you have? What dex equips do you have already? Those 3 are already on need to know basis for helping someone with a low dex thief.