It's just the matter of the schedule,that is ,if it is conve

if可以理解为“是否”,相当于whether.
整句话的意思可以理解为:这仅仅是时间安排的问题,也就是说,你现在是否方便.
that is 是插入语成分,作用事引出后面的解释说明
if it is convenient of you right now是同位语