I know two ways to schedule tasks on Crom:
1 - execute the command crontab -e
that opened a window giving a slight description of how you can schedule the tasks in cron, where you can simply paste your already created cron, at the end the window should look like this:
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
25 11 * * 1-5 wget -q --spider http://10.24.0.42/felipe_projetos/DD/CREATE_TABLE.NULL.IN.php
In this example there is no need to define a user.
2 - Edit or create your cron in /etc/crontab-d/meucron
vi /etc/cron.d/meucron
now paste your cron
25 11 * * 1-5 root wget -q --spider http://10.24.0.42/felipe_projetos/DD/CREATE_TABLE.NULL.IN.php
Note that in this second method I set a user to perform the action.
After editing/creating your cron and saving it, restart crontab.
For this second method you must be root to create or edit files in /etc/cron. d/