Desert Storm has one piece of folklore attached to it that costs alliances real matches, and First Fun has answered it directly. We will start there.
Sandbagging does not work
The theory goes that if your registered members remove their gear and decorations before sign-up, the alliance looks weaker and draws an easier opponent. It does not. Matchmaking is calculated from the real power of all registered players, and stripping equipment before registering does not affect it. All you have achieved is fielding a team that forgot to put its gear back on.
Registration is Monday to Wednesday, and it is not yours to do
R4 and R5 register participants and select the battle time between Monday and Wednesday. The previous participant list is saved, which makes the officers' job quick — and also means an inactive member can stay on the roster for weeks unless somebody checks it.
One rule to hand to anyone thinking about an alliance move: leaving the alliance after signing up removes your eligibility even if you rejoin before the battle. Not "you lose your slot and get it back" — you are out for that battle. If a member is planning a switch, it happens after Desert Storm or not that week.
Task Force A and Task Force B are two separate events
| Matchmaking | separate for A and B |
| Results | independent — one can win while the other loses |
| Main participants | 20 per task force |
| Substitutes | 10 per task force |
| Entry priority | main participants first |
Because the two forces are matched separately, splitting your roster evenly is usually worse than deliberately loading one. An alliance that puts its strongest thirty into A and its next thirty into B gets one force that can win its bracket instead of two that are middling in theirs.
There is no way back in
Once you exit Desert Storm Battlefield you cannot re-enter. If what you actually want is to look at the world map, tap the base icon in the bottom right — that returns you to the map view without leaving the battlefield. This is the mistake that ends people's events fifteen minutes in.
Sources: First Fun’s official English help centre — When can I sign up?, Leaving and rejoining after sign-up, Task Force A vs Task Force B, Why can't I re-enter?, How is matchmaking done?