mapping for the 1st time as a new player

i am a fairly casual arpg player

played a lot of d2 and d4
sadly didnt play much poe1 so i am not as familiar with poes end game systems

so i am a little lost when it comes to maps

i guess my main priority for now is experience points since i just want to get my character as leveled as possible before trying to push higher tier maps

what should i be doing at prioritize xp in maps?

also i currently have 4 points in ascension.. what levels and how many points should i have in ascension before focusing on maps?

IMO all this comes down to what build you're playing. I would definitely prioritize leveling but some meta builds can do like T10 maps right out of interludes with leveling gear. In general, a lot of good gear is min level 65 - 75 (or maybe even 78). Once you hit a good level then I would just buy some cheap, good gear on trade for a few exalts ideally.

The next thing to look for are areas of "corruption" they'll have red "blood" sort of effects and have an icon saying stuff about coalesced blood. Start doing nodes towards them. Don't worry too much yet about super "juicing" the maps, but definitely try to experiment with how hard of content your character can do. The harder the content the better the XP gain.

In these corruption / coalesced blood zones there will be a special boss in the middle with a special icon. If you beat that you get an item that grants passive points on your atlas tree, this lets you enhance the maps to do things like give you higher essence chance, add more rare monsters, etc.

Once you beat the first corruption zone, you can start looking for another one. The next one will require you to use a higher tier map to run it. In total there will be 4 of these granting 20 out of 40 atlas points.

The next 20 atlas points come from clearing "unique" nodes on your atlas. You'll see they have special icons - note though they aren't actually unique and can appear multiple times. There's 10 types of these maps and clearing that type of unique map once will drop a book giving you 2 atlas points.

The next part of your atlas is about boss killing, juicing the abyss, breach, expedition, etc. events and all that. For now just focus on exploring your atlas and doing the content you like (eg, abyss) with some tablets that force add that content to the map and you'll probably figure it out as you go for these things.

Have fun!