How to assign characters to coordinates on elliptic curve using Koblitz algorithm

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Hi, our group is making project on text encryption using Koblitz in Elliptic curve cryptography. We have used the elliptic curve y^2=x^3+2x+9(mod 37), a=2,b=9. We have got 43 points & generated public as well as private key. We are stuck on how to assign characters to coordinates on elliptic curve using Kolbitz algorithm.