The informal statement can be very straightforward. It's a simple statement of . . .

"Here's what I'm interested in doing. . . .

Here's why I'm interested in that. . . . 

Here's what I think will be useful for that project. . . .

This means that you should include three or four references to materials and activities (such as interviewing someone . . .) that you think would be helpful to your in working on your project. (No, you do not have to do an interview, that's just one possibility.)

If you include a reference to a source on the web, be sure to give its full reference (not just the URL). For a web page your full reference should look something like this (include as much of this material as is available for the site[s] you are looking at):

For this assignment you may turn in the sources information any way you like --  except that if you are using a web site include the name of the web site (and author, if it has an author) in addition to the URL.  (That is, do not just cite the URL.)

Roufs, Timothy G. and Kathleen Smyth Roufs. Sweet Treats. accessed 8 February 2019. http://www.d.umn.edu/cla/faculty/troufs/anthfood/SweetTreats.html#title.

For the "Promissory Abstract" and "Working Bibliography" (that are due in two weeks) and for the Case Study itself (due at the end of the semester) you need to use APA or MLA or Turabian/Chicago Style or a standard scientific method.  Which of those you use is up to you.

What do you think?"

Or, it can be something like . . .

"I'm thinking about doing a project on X or Y, but can't make up my mind.

Here's what I'm interested in, and why. . . .

Here are some things that look like they might be useful for the project. . . .

This means that you should include three or four references to materials and activities (such as interviewing someone . . .) that you think would be helpful to your in working on your project. (No, you do not have to do an interview, that's just one possibility.)

If you include a reference to a source on the web, be sure to give its full reference (not just the URL). For a web page your full reference should look something like this (include as much of this material as is available for the site[s] you are looking at):

Roufs, Timothy G. and Kathleen Smyth Roufs. Sweet Treats. accessed 8 February 2019. http://www.d.umn.edu/cla/faculty/troufs/anthfood/SweetTreats.html#title.

What do you think?"

A more formal statement (a "Promissory Abstract") of what you eventually decide upon isn't due for another two weeks.