1,024 ways is the ways-to-win layout on a five-reel, four-row grid. Each reel shows four symbols, so there are 4^5 = 1,024 left-to-right paths, and every one of them is active on every spin.
It works exactly like 243 ways, with one more row. Matching symbols on adjacent reels starting from reel one pay, and duplicates on a reel multiply the number of winning ways.
The extra row means more symbols in view and more frequent small wins, but the paytable is lower per way to compensate, so 1,024 ways is not more generous than 243. Some games start at 243 ways and switch to 1,024 during a feature by adding a row; see grid expansion.
Six-reel games with four rows reach 4^6 = 4,096 ways, using the same arithmetic.