[Queries] Problem Matching Record Count To A Field

This is kind of a weird problem, and everything I've learned about access has been on my own through empirical experimentation so forgive my if my description doesn't make sense, or if I overlooked something really simple. (Apologies for that, I've looked over all the guides on queries and record counting I could find and got nothing on this.

I can't figure out a better way of explaining my situation so I'll do the best I can.

I need to make a query that shows the number of people that have registered for a class.
In one table I have the primary key Schedule ID which is the unique class, which is linked in one-one relationship with another field of the same name. In the second table with that field I have the field schedule ID which shows up multiple times, for each student enrolled in the course, second is the field Participant. There is the following data:
Schedule ID...Participant
1 ................ <name1>
1 ................ <name2>
1 ................ <name3>
4 ................ <name4>
4 ................ <name5>

What the result of the query should look like is this:

Schedule ID...Number of participants
1 ................ 3
4 ................ 2


But instead I get
Schedule ID...Number of participants
1 ................ 5
1 ................ 5
1 ................ 5
4 ................ 5
4 ................ 5

I have tried various variations of the Count and Dcount functions but I always wind up with that result (if it works at all)

This is the expression I am using:

Expr1: DCount("[Schedule ID]","Class Roster")

where "Class Roster" is the name of the Table that Schedule ID is located. I have tried changing it out with the name of the first table, and I have tried using participant instead of Schedule ID, but neither works. So far I've been able to use a crosstab query to get something roughly what I want but I think the assignment calls for a regular query.

Again, sorry if this doesn't make any sense, I did my best to explain it, and I couldn't find an answer anywhere. Thanks in advance for any help!

Oh, by the way, it's access '03 that I am using.


UPDATE: I have a second problem I'm trying to solve, and this one seems more confusing than the first to me. I have a table with the following fields:

Project Name, Task name, employee ID, Production Week, and Hours Worked. The first two being text and the last 3 being numerical.

I need to create a query that totals up the hours worked for each employee (one employee ID can show up under multiple projects/tasks) and returns the total hours in a particular week (week 20) of each employee that has worked over 40 hours, and only the ones that have worked over 40 hours. I can not figure out how to create a field that will sum up the hours worked for a given employee, nor can I figure out how to show only rows where the total hours record exceeds a certain amount. It seems like I would want a conditional like an IIF statement but those seem to be only for returning values, not showing/hiding.