Problem installing SuiteCRM 8 on Centos 7

Hi, I’ve found a most useful resource at the suitecrm website on installing SuiteCRM 8 on Centos 7. Everything seems to go fine, until I try to access the website to install the package. I’m confronted with:

System Check Acceptance

Errors have been detected during compatibility check. In order for your SuiteCRM Installation to function properly, please take the proper steps to address the issues listed below and either press the recheck button, or try installing again.

Status

Component

Writeable Custom Directory

The Custom Directory exists but is not writeable. You may have to change permissions on it (chmod 766) or right click on it and uncheck the read only option, depending on your Operating System. Please take the needed steps to make the file writeable.

Writable Cache Sub-Directories

The files or directories listed below are not writeable or are missing and cannot be created. Depending on your Operating System, correcting this may require you to change permissions on the files or parent directory (chmod 755), or to right click on the parent directory and uncheck the ‘read only’ option and apply it to all subfolders.

Please fix the following files or directories before proceeding:
/var/www/html/crm/cache/
/var/www/html/crm/cache/images
/var/www/html/crm/cache/layout
/var/www/html/crm/cache/pdf
/var/www/html/crm/cache/xml
/var/www/html/crm/cache/include/javascript

Writable Modules Sub-Directories and Files

Warning: Not Writable

Please fix the following module directories and the files under them before proceeding:
/modules

Writable Upload Directory

Warning: Not Writable

Location of your PHP configuration file (php.ini):
/etc/php.ini

Can anyone please assist ? What am I doing wrong?

Regards,

Charl