lets take a little historical view on this map (from RO-history pov) first:
Back in Mod days... this map was missing two exits - one to Petrol Yard (PY) from axis left hand and one to Cetral Yard (CY) from right hand. This map was kinda hell for teams with weaker attacking power since Alies could nail Axis on 3 possible exits from spawn. However once CY was capped than we are getting to presence...
Today I can see that more usuall tactic for this map is strong attack on PY and than press on respawning Alies running to CY, together with attacking and capping CY.
The main argument for this is that well defended PY cannot be capped very well later. This is true in case you are defending PY against not very well attacking team. If Axis team is a little clever (and well coordinated) than they will destroy your defence on PY. It is not easy but it is not so time consuming. This is first critical moment on this map. Well defending Alies team can hold PY very long and than time is missing for attack on Construction Hall (CH).
Imo it is not important if you attack first PY or CY. You just have to have plan what to do next. So if you decide your tactic to be attack through PY and than CY, ok, but be sure you have well planed attack on CY.
If you decide to attack CY first than be prepared for strong defence and be sure every member in team knows what to do next when going to PY.
Once CY and PY are capped than we can focus on Construction Hall and Garage.
Garage in NOT important for defence (in terms you do not have to cap it back as Alies). If you think that it is important than you still need some games on this map first.
Last Critical objective - Construction Hall... easily you just need little luck to cap this. If Alies are well spread on this map, than it is Hell for Axis to get in, survive so long that you can start cap, survive first wave of respawned Alies ... survive until it is capped... Since there are 5 entries into CH than it is not so difficult to defend in 8 vs 8 setup.
This map is one of most played since mod days and than you have to expect that all will know how to play on this map. On the other hand you will see that this map perfectly shows when there is a team with good teamplay and chemistry against you... have fun