It's also good to know the degree of unsaturation formula:
(2*C + 2 - H)/2 ... in this case (2*4 + 2 - 10) = 0 ... so no double bonds or rings. So the isomers are only saturated alcohols and ethers. After that, just draw it out...
Keliao said it is 7 isomers. But I am getting 8 isomers.🙁 Can you explain me how did you get it? please. I draw them out then count the possible location of the Hydrogen for the isomers.