The C7(b9,b13) belongs to the category of altered dominant 7th chords (general: V7alt). These are dominant 7th chords with one ore more of the altered tensions b9, #9 or b13. The #11 has a special role, since it rather comes along with the natural tensions 9 and 13. Please look up the description for a 7(#11) chord. The altered tensions b9, #9 and b13 mainly occur, when the V7 chord resolves from V to I, like from the C7 to Fmaj7 or Fm7. You may sometimes also stumble across the universal notation C7alt for a C altered chord, saying that the player can decide by himself which altered tensions he/she wants to use. But usually you can decide that by yourself anyway, since altered tensions are mostly interchangeable and combinable.
The b9 Db is located a minor 2nd above a root tone, but will always be written as b9 and never ever as b2 (the 2 only occurs in sus2 chords). The b13 Ab is located a minor 6th above a root tone, but it is written as b13 in the chord symbol and not as b6, because it extends the 7th rather than replacing it. Besides that b6 chords will normally be reinterpreted as inversion of another chord and then often be written in slash chord notation.
A C7(b9,b13) has the notes C (1), E (3), Bb (7), Db (b9) and Ab (b13). There will hardly be space (physically and acoustically) for a 5th, that on the guitar will normally be abandoned for the b13, that is located 1 fret higher.
You can see a C7(b9,b13) chord as a Bbm7(b5)/C slash chord, a Bb half-diminished chord with C in the bass. Especially when a bass player delivers the root (but even without), you can play Bbm7(b5) instead or additionally to a C7(b9,b13) chord.
Example chord progressions Gm7 C7(b9,b13) Fmaj7 Bbm7 C7(b9,b13) Fm9 Gm7(b5) C7(b9,b13) Fm7
Last one with Bbm7(b5) instead of C7(b9,b13): Gm7(b5) Bbm7(b5) Fm7 (you just have to slide up the Gm7(b5) by 3 frets!)