The most correct way to make a block is to first setup your own module and then making a block inside this module.
I cannot go into all the details for making modules but in this case you should create your own directory under the /modules dir and it should contain a file named xoops_version.php looking like this:
$modversion['name'] = <name>;
$modversion['version'] = <version>;
$modversion['description'] = <description>;
$modversion['author'] = <author>;
$modversion['credits'] = <credits>;
$modversion['help'] = <help>;
$modversion['license'] = <license>;
$modversion['official'] = 0;
$modversion['image'] = "images/<an optional image to display in admin section>";
$modversion['dirname'] = <name of dir under modules>;
$modversion['hasAdmin'] = 0;
$modversion['hasMain'] = 0;
$modversion['blocks'][1]['file'] = <block filename>;
$modversion['blocks'][1]['name'] = <block name>;
$$modversion['blocks'][1]['description'] = <description>;
$modversion['blocks'][1]['show_func'] = <function to invole to show render the block>;
$modversion['blocks'][1]['template'] = <any template file you might be using to render the block>;
This will basically setup a module with one block and without and admin or main stuff and provides a basic framework to install your block into XOOPS and manage it's display through teh configuration tools.
How to setup the rest is a bit too much to get into. Best read up and have a look at the sample XOOPS module if that's still available.