How to apply patches and add functions

[prateekshukla1108]

Hello,
I am trying to use functions which requires selmon to apply it but I don't know how to apply patches in it
please guide
the functions are
// Define the function to shift view
void
shiftview(const Arg *arg) {
Client *c;
unsigned int seltags;
unsigned int newtags = 0;

seltags = selmon->tagset[selmon->seltags];

if(arg->i > 0) {    // left circular shift
    newtags = (seltags << arg->i) | (seltags >> (LENGTH(tags) - arg->i));
} else {            // right circular shift
    newtags = seltags >> (- arg->i) | seltags << (LENGTH(tags) + arg->i);
}
newtags &= TAGMASK;
if (newtags) {
    view(&((Arg) { .ui = newtags }));
    for (c = selmon->clients; c; c = c->next)
        if (c->tags & newtags)
            focus(c);
}

}

void
movewindowtows(const Arg *arg) {
if (!selmon->sel)
return;
int newtag = selmon->sel->tags;
if (arg->i > 0) {
newtag = newtag << arg->i;
if (newtag > (1 << (LENGTH(tags) - 1))) // Wrap around
newtag = 1;
} else {
newtag = newtag >> (-arg->i);
if (newtag < 1) // Wrap around
newtag = 1 << (LENGTH(tags) - 1);
}
selmon->sel->tags = newtag;
focus(NULL);
arrange(selmon);
}