Before trying to close your phone, try to turn it on, to charge it and to check if it works correctly. Like this you can solve any issue without the need of opening it back

To close your phone you could use the original adhesive if you were careful enough during removal, though this could lead to later unsealing of the case; hence I suggest you to use a specific glue like the B-7000 glass glue

Put either the adhesive or the glue around the perimeter of the phone (not the rear glass) in the most homogeneous way possible

After application gently close the rear glass and apply some pressure

You should apply even pressure on the whole screen for many hours, you should use the screen clamps to guarantee perfect adhesion

If your phone looks like the last picture simply heat it up again and remove all the adhesive with isopropil alchool and start again. otherwile it could open at any moment

Don't worry if some glue pops out from the borders, you'll be able to remove it once dried either with your fingernails or isopropil alchool