Add a new "Embed" block and select "Code Snippet".
Enter the following:
<iframe
style="width:99%; height: 800px;"
allow="fullscreen; clipboard-read; clipboard-write; keyboard-map "
src="https://app.devmatch.io/embedded/welcome?projectId=270&candidateId=123"></iframe>
Where projectId is your projectId. Ignore candidateId for now.