You can find the MEME Motif discovery tool here: http://meme-suite.org/tools/meme

1. First, you can enter sequences in which you want to find motifs ① .And  Select the number of motifs ② , we also suggest you to select some advanced options in ③ .
   

   

2. You can click “Start Search” to start the Motif discovery, and it will go to a waiting page like:
   

   

   You can also bookmark this page or use the Recent Jobs menu at the left ④ to access your job's results later.

3. After the job is completed, it will go to a page like:
   

   

4. You can click “MEME HTML output” button ⑤ and check the detail result of Motifs:
   

   

   You can also use the code vision of MEME, detail documentation please check : http://meme-suite.org/doc/meme.html