Hints:
Black has a 2 point sente move (with 7 points threat) at A. Likewise, white has a 2 point sente at B. In addition, there are gote endgames, ranging from 1 to 10 points.
Given the big gote moves on the board, the sente endgames aren't proper sente moves yet (the opponent will not answer the threat, but pick a bigger gote). Start with the biggest gote endgame (M1), then find the right timing for the sente / reverse sente moves!
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[13]KM[20.00]
CR[lm]AW[ca][ka][la][ab][bb][cb][kb][mb][ac][cc][ec][fc][gc][jc][kc][lc][mc][ad][md][ae][ce][ee][fe][ie][je][ke][me][af][cf][mf][ag][cg][eg][fg][ig][jg][kg][mg][ah][ch][mh][ai][ci][ei][hi][ii][ji][ki][mi][aj][bj][cj][mj][ck][ek][hk][ik][jk][kk][mk][cl][ml][cm][gm][hm][im][jm][km][mm]AB[da][ea][fa][ha][ia][ja][db][fb][gb][hb][jb][dc][cd][dd][ed][fd][gd][hd][id][jd][kd][ld][he][bf][df][ef][ff][gf][hf][if][jf][kf][lf][bg][gg][bh][dh][eh][fh][gh][hh][ih][jh][kh][lh][gi][dj][ej][fj][gj][hj][ij][jj][kj][lj][fk][dl][el][fl][gl][hl][il][jl][kl][ll][fm]LB[ic:B][bd:A]C[20 points komi, black to win the game!]
(;B[lm]
;W[lk]
(;B[li]
;W[lg]
(;B[bd]
;W[be]
(;B[le]
;W[ic]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[Yes, black wins by 1 point! RIGHT])
(;B[ic]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[Jigo.
(reverse sente was played too early)]))
(;B[le]
;W[ic]
(;B[hc]
;W[de]
(;B[bd]
;W[be]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[Yes, black wins by 1 point! RIGHT])
(;B[dg]
;W[bd]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(sente was played too late)]))
(;B[bd]
;W[be]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[Yes, black wins by 1 point! RIGHT]))
(;B[ic]
;W[le]
(;B[bd]
;W[be]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[Jigo.
(reverse sente was played too early)])
(;B[de]
;W[dg]
(;B[bd]
;W[be]
;B[di]
;W[dk]
;B[dm]C[Jigo.
(reverse sente was played too early)])
(;B[di]
;W[bd]
;B[dk]
;W[dm]C[White wins by 1 point.
(reverse sente was played too early)]))))
(;B[bd]
;W[li]
(;B[lg]
;W[be]
(;B[le]
;W[ic]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[Jigo.
(sente was played too early)])
(;B[ic]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(both sente and reverse sente was played too early)]))
(;B[be]
;W[lg]
(;B[le]
;W[ic]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[Jigo.
(sente was played too early)])
(;B[ic]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(both sente and reverse sente was played too early)]))
(;B[ic]
;W[lg]
;B[be]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(both sente and reverse sente was played too early)]))
(;B[ic]
;W[li]
(;B[lg]
;W[le]
(;B[de]
;W[dg]
(;B[bd]
;W[be]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(reverse sente was played much too early)])
(;B[di]
;W[bd]
;B[dk]
;W[dm]C[White wins by 2 points.
(reverse sente was played much too early and sente was played too late)]))
(;B[bd]
;W[be]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(reverse sente was played much too early)]))
(;B[bd]
;W[be]
;B[lg]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 1 point.
(reverse sente was played much too early)])))
(;B[bd]
;W[lm]
(;B[lk]
;W[li]
(;B[lg]
;W[be]
(;B[le]
;W[ic]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[White wins by 1 point.])
(;B[ic]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[be]
;W[lg]
(;B[le]
;W[ic]
;B[hc]
;W[de]
;B[dg]
;W[di]
;B[dk]
;W[dm]C[White wins by 1 point.])
(;B[ic]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[ic]
;W[be]
;B[lg]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[ic]
;W[lk]
;B[li]
;W[be]
;B[lg]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 3 points.]))
(;B[ic]
;W[lm]
(;B[lk]
;W[li]
(;B[lg]
;W[le]
(;B[de]
;W[dg]
(;B[di]
;W[bd]
;B[dk]
;W[dm]C[White wins by 3 points.])
(;B[bd]
;W[be]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[bd]
;W[be]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[bd]
;W[be]
;B[lg]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 2 points.]))
(;B[bd]
;W[lk]
;B[li]
;W[be]
;B[lg]
;W[le]
;B[de]
;W[dg]
;B[di]
;W[dk]
;B[dm]C[White wins by 3 points.])))