The indefinite adjective algún and the indefinite pronoun alguno

Question

Please provide clearer explanation of rule, 'Don't mix the indefinite adjective algún with the indefinite pronoun alguno. You can never use alguno with a noun!'. Thank you

Answer

Hola Paris,
Sorry about the late response. 
What we mean here is that algún is an adjective and as such, it accompanies a noun "algún estudiante", but "alguno" can also be a "pronoun" and as such, it won't be followed by a noun. But we forgot to attach the link to the lesson explaining the pronouns so I have just done that. Here is the link for you so you can see what we are referring to when we say "don't mix them up".
Alguno
I hope this helps.
Saludos
Inma