IUI questions

So if this month with letrozole and timed intercourse are unsuccesful we are moving onto an IUI. The clinic said to call then cd 1 to let them know it's my day one then I will take letrozole 7.5 mg cd 3-7 and call them when I have a positive opk in the morning and will go in the afternoon for an IUI. No ultrasounds to check follicles or anything. No trigger shot. Has anyone heard of IUIs this way?