A child can often read 3:45 correctly and still put the hour hand exactly on the 3 when asked to draw it. Reading is recognition; drawing requires knowing that the hour hand moves continuously and sits three-quarters of the way to the 4. The draw-the-hands sheets exist for precisely that gap, and they are the faster diagnostic of the two.
The clock faces are drawn as vector graphics with proper tick marks and correctly proportioned hands, so what the child reads on paper matches what a real clock does.
The reason elapsed time is hard has nothing to do with clocks. It is that 40 minutes after 2:35 is not 2:75, and a child who has spent four years in base ten has to hold that exception in mind while doing everything else. The difficulty settings step from whole hours, to half and quarter hours, to crossing the hour boundary — which is where it gets genuinely hard.
The calendar and daily-schedule sheets round it out: days, months, ordinal dates and matching activities to times. The calendar questions use fixed facts rather than today's date, so a printed sheet is still correct next month.
Which grade should start telling time?
Grade 1 for the hour and half hour, Grade 2 for five-minute intervals, Grade 3 and up for the minute and for elapsed time. Each page lists the grades it supports.
Are the clocks analogue or digital?
Analogue faces, with digital times used in the question or answer depending on the activity. Reading an analogue clock is the skill that needs the practice.
Does the calendar sheet use the current month?
No, deliberately. It asks about fixed facts — how many days in March, what the third Tuesday is on a given calendar — so the printout does not expire.