These images are identical, they've been duplicated for easier reading.
To start off with how the map plays, you should understand the main parts of the map. These include three separate lanes. The 1st being the 1-2 line, the 2nd being the 4-5 line, and the last being the 8 line.
The 1st lane plays well together with the 2nd lane. Heavy tanks should always head over to the 1-2 line, as it is the main important position that controls a large portion of the map. Mediums and lights have more options. They can opt to head to the 2nd lane and attempt to deny the E5 and F5 positions (the cubby), which is a high-risk position. These are firing positions from within the Abbey itself. Simply positioning on the D5 and G5 inclines will give you easy early damage on any tanks heading into the Abbey.
Once you've established control over the middle or no tanks remain there, you can turn around and head over to the first lane to assist your heavies. Pushing through the middle is highly dangerous as Tank Destroyers will oftentimes be camping around the flag cap or on the perch over looking the base from the 1-2. This 1st lane should be a constant brawl between heavies, tank destroyers and mediums. If you see there are no tanks on the D1 corner or G1 corner, from the Southern and Northern spawns respectively, you can push down the 1 line. If you've successfully pushed into the 1 line with another tank, you can begin flanking the enemy which will result in a win if done correctly. Try not to overextend if there are no tanks to help you.
Tank destroyers should be going towards the 1st lane as it is the best part of the map to be in, though there are other spots such as around the spawn hills or perched overlooking cap from the 1-2 line, but overall, being in the fight is a lot more important than gambling on if the enemy pushes through towards you.
Players should really avoid pushing the final lane (8 line), as it is mainly useless for map control and overall positioning. Once you've headed down the 8 line, you're essentially stuck because there's really only a single spot (E7) from which you can cross back to the middle area without having to return all the way to the initial entrance for the line. Heavy tanks in particular will be simply left to either try to push all the way down or return to base. If the enemy is waiting for you down the lane, you will likely lose the fight as it is very difficult to breakthrough even against lesser numbers. Capping as well is rarely even an option at all due to the cap points being very open and easy to spot so it's generally not worth it.
To summarize, the 1st lane and the 2nd lane work together to assert map control, both have angles from which they can assist one another and also provide coverage for many other portions of the map. This makes these two lanes the most important parts of the map, where the games will be either won or lost based on the results of the engagements. At the very least, do not head down the 8 line or else you'll generally be nothing more than a burden to your own team.