Grammar

Sanjay tells you that "however" should not be used to begin a sentence. Let me quote Garner's Modern American Usage (3rd edition, 2009, Oxford University Press) on the topic.

"It seems everyone has heard that sentences should not begin with this word -- not, that is, when a contrast is intended. But doing so isn't a grammatical error; it's merely a stylistic lapse, the word But or Yet ordinarily being much preferable. The reason is that However -- three syllables followed by a comma -- is a ponderous way of introducing a contrast ..."

You may use However to begin a sentence, but consider whether it is the best word choice.

There is no need to use "However" at the beginning of  a sentence.  "However" is used to connect two independent clauses.  

If the training time is too short for the new employees, they will not have time to understand their future jobs well.

There is no doubt that if we want to develop our country or fix it, we must begin by reforming ourselves and then we begin to develop our country and reform it. For a long time and I ask myself why my country Syria is considered one of the richest Arab country and I don't see this rich reflected on the citizen where Syria owns petroleum riches and is considered as producer and non-imported in many sides, so if these reflect on the citizen then he will become in an excellent situation, but there should be many suggestions and solutions to achieve this thing.

The first suggestion is developing and improving  the operations of oil exploration and these take a great effort and many techniques because maybe there are unexplored reserves especially in some Syrian territories which they have not been prospected yet. And I propose building very sophisticated refineries in the oil-producing regions of Syria and this step has many economic benefits: to provide new employment in the areas that need work, establishing petro chemical industries resulting from the petroleum refining process, such as fertilizers and plastic industries and other. Moreover our government should not raise the price of petroleum products and secure internal consumption needs of the citizens.

Since the oil wealth is very precious  and we are a producer of oil, the state must make the oil production in favor of the government and the citizens together and distribute the oil budget to citizens and incorporating the oil revenues to the budget.  So this would make the citizen does not think in livelihood and makes him think in improving himself and his abilities, therefore these will be reflected on the country and develop it in all respects.

In Conclusion, if we affirm these suggestions in our country, a lot of problems would be solved including the increasing migration of young people, leading to the availability of employment opportunities and thus make the talents of young people grow inside not outside Syria.