Epson 1500 - Manual (Page 135)

4. Insert a stack of paper face-up into the cassette with the
corners of the paper beneath the two tabs at the back of the
paper cassette.
Note:
Do not load paper above the marks on the cassette.
5. Insert the paper cassette into the front of the slot of the lower
paper cassette unit and push it firmly into place.
Options 5-21