I have only just started it myself and haven't worked out everything that you have to do myself yet. Hopefully when I solve a few more clues it will become clearer.
In the meantime
25a = an 8 letter anagram of 9 letters and you discard an A so it is a type 4 answer
24 = a type 4 answer also, the parsing leads to 7 letters discard an I and you get the 6 letter definition
26 across - likewise discard an E
23d the parsing = 5 letters but the definition is 6 letters, add a G
(type 3 answer)
14d add an A to the parsing for (slab illuminated within) to get the definiion (earth perhaps) - (type 3 answer)
23a and 15d are anagrams - but at this stage I don't know whether they are type 1 or 2